Distribution of retroperitoneal tumors. A, We classified tumor locations into 5 groups depending on their relationships with the IVC and renal vein. The numbers within the circles are the number of tumors in each location. B, Tumor locations in individual patients. The numbers in circles are the patient numbers shown in Table 1. Underlined patient numbers are tumors that adhered to an adjacent major vessel. Adhered to the IVC: 1, 6, 13, 15, and 16; adhered to the splenic vessel: 5 and 11; adhered to the renal vein: 2 and 9; and adhered to the SMV: 17. IVC indicates inferior vena cava; LL, left lower area; LU, left upper area; Post, posterior to the IVC area; RL, right lower area; RU, right upper area; and SMV, superior mesenteric vein.
Preoperative CT and intraoperative findings of patient 10. A, Preoperative CT finding showing a large tumor located along the posterior portion of the IVC and portal vein. B, The tumor was identified after kocherization of the duodenum. It was located along the posterior IVC and adhered to the vessel. C, Laparoscopic view during dissection. D, Laparoscopic view after resecting the tumor. During dissection, the proximal left renal vein was injured and repaired with an intracorporeal suture (asterisk). CT indicates computed tomography; D, duodenum; G, gallbladder; H, hepatoduodenal ligament; IVC, inferior vena cava; M, mass; P, portal vein; and R, renal vein.
Ahn KS, Han H, Yoon Y, Kim H, Lee T, Kang S, Cho JY. Laparoscopic Resection of Nonadrenal Retroperitoneal Tumors. Arch Surg. 2011;146(2):162–167. doi:10.1001/archsurg.2010.342
Laparoscopic resection of primary retroperitoneal tumors is a challenging procedure because access is difficult due to the deep, posterior location and adjacent major vessels.
To assess the safety and feasibility of laparoscopic resection of primary nonadrenal retroperitoneal tumors.
Data on 20 patients with a diagnosis of primary retroperitoneal tumor who underwent laparoscopic resection from August 1, 2003, to June 30, 2009 were analyzed.
Twenty patients (12 men and 8 women; median age, 45.5 years) were included in the review. The tumor sizes ranged from 2.0 to 9.5 cm in diameter (median, 4.7 cm). In 10 patients, tumors were adherent to adjacent major vessels (ie, inferior vena cava, renal vein, superior mesenteric vein, or the splenic vessel). Postoperative examination of the samples revealed that lymphangioma (7 [35.0%]) was the most common tumor type, followed by ganglioneuroma (3 [15.0%]), schwannoma (2 [10.0%]), paragangolioma (2 [10.0%]), and Castleman disease (2 [10.0%]). The median operative time was 117.5 minutes and the median estimated blood loss was 50.0 mL. One operation (0.05%) was converted to laparotomy due to intraoperative bleeding. Postoperative complications occurred in 2 patients (10.0%), both of whom were treated conservatively. The median length of the postoperative hospital stay was 5 days. Neither tumor size nor the presence of adhesions to adjacent vessels affected the perioperative or clinical outcomes.
Laparoscopic resection of retroperitoneal tumors is feasible even when a tumor is large or adheres to adjacent vascular structures if there is no evidence of malignancy based on preoperative radiologic studies.
Since laparoscopic adrenalectomy was first reported in 1992,1 it has become the preferred method for removing most types of adrenal tumors.2- 4 However, reports on the laparoscopic approach to nonadrenal retroperitoneal tumors are limited because the procedure is difficult due to the deep location, narrow operative space, and proximity to major vessels, such as the aorta and inferior vena cava (IVC).5- 11 For these reasons, most retroperitoneal tumors are removed by laparotomy, which requires a larger incision and results in more postoperative pain and a longer recovery time compared with laparoscopy.
Recently, due to advances in laparoscopic techniques and instruments, indications for the laparoscopic approach to the retroperitoneal area have been broadened to include pancreatic12- 14 and aortic procedures.15,16 Therefore, we reasoned that if a safe approach to the retroperitoneum is possible by laparoscopy, the well-known advantages of laparoscopy, which are reduced postoperative pain, faster recovery, and better cosmesis, can be realized for the treatment of retroperitoneal tumors. In this study, we evaluated our experiences with laparoscopic resection of primary benign nonadrenal retroperitoneal tumors in various locations with regard to feasibility and safety.
Between August 1, 2003, and June 30, 2009, a total of 155 patients underwent laparoscopic (n = 121) or open (n = 34) resection of retroperitoneal tumors. Of these, 121 patients who had a tumor of adrenal gland origin were excluded. A primary retroperitoneal tumor was diagnosed in the remaining 34 patients; 20 patients (58.8%) underwent laparoscopic excision and 14 patients (41.2%) had open excision. Laparoscopic excision of a retroperitoneal tumor was indicated when the diagnosis of a benign tumor was made based on findings from preoperative radiologic studies. We excluded patients who had tumors larger than 10 cm or features of malignancy, such as the presence of irregular margins and definite invasion to adjacent organs based on preoperative radiologic findings. Even for patients without symptoms, laparoscopic excision was used because of the possibility of misdiagnosis17- 19 and malignant transformation.19,20
We retrospectively analyzed the clinical outcomes of 20 patients who underwent laparoscopic excision of a primary nonadrenal retroperitoneal tumor. The clinical outcomes, including operative time, estimated blood loss, postoperative hospital stay, and complications, were evaluated with respect to tumor size and adhesions to adjacent major vessels. Finally, the outcomes of this study population were compared with the outcomes of 14 patients who underwent open excision.
Tumor locations were classified into 5 groups based on radiologic findings (computed tomography or magnetic resonance imaging) and relationships with the IVC and renal veins (Figure 1). Postoperative surgical complications were defined and graded, as described by the proposed Clavien classification system.21
Under general anesthesia, the patient was placed in the supine or lateral decubitus position, depending on the approach chosen. Three to 7 trocars were used as required during the operation, and a 30° or flexible laparoscope was used. Dissection and mobilization were performed using electrocautery and ultrasonic shears (Harmonic scalpel; Ethicon, Cincinnati, Ohio; or SonoSurg; Olympus, Tokyo, Japan).
Access for tumor resection in the right side was facilitated by performing the Kocher maneuver on the duodenum, mobilizing the hepatic flexure and ascending colon, and retracting the right liver upward. Right retroperitoneal structures, including the right adrenal gland, the posterior portion of the pancreaticoduodenal unit, the right renal vein, and the IVC, were approached using these maneuvers (Figure 2). Tumors in the left side were exposed by mobilizing the splenic flexure of the colon and dividing the splenorenal ligament from the inferior splenic pole, thereby allowing the spleen and tail of the pancreas to move upward or medially. Using these procedures, left retroperitoneal structures, including the left adrenal gland, the left renal vein, and the aorta, could be approached. When a tumor was located in the right or left lower area, it was approached via retroperitoneal dissection after applying upward medial traction to the bowel and mesentery.
Tumors were dissected and mobilized from adjacent structures, and feeding vessels were divided using either metallic clips or Hem-o-lok clips (Weck Teleflex Medical, Research Triangle Park, North Carolina). After meticulous hemostasis and saline irrigation, a drain was placed around the surgical field. The resected specimens were placed in individual protected bags and extracted through a small incision that was created by extending the 10-mm working port.
All values are expressed as median (range) or as mean (SD). Statistical analysis was performed using the Mann-Whitney test, Pearson χ2 test, and Fisher exact test in the Statistical Package for the Social Science for Windows (release 15.0; SPSS Inc, Chicago, Illinois). Differences were considered significant at P < .05.
The detailed characteristics of the tumors are summarized in Table 1. The patients included 12 men and 8 women with a median age of 45.5 years (range, 21-69 years). Tumors in asymptomatic patients that were detected incidentally during health screening were most common (13 [65.0%]), followed by tumors in patients with abdominal or flank pain (4 [20.0%]). The median tumor diameter was 4.7 cm (range, 2.0-9.5 cm). The most common tumor site was the left upper area (7 [35.0%]), followed by the right upper area (4 [20.0%]), right lower area (4 [20.0%]), left lower area (3 [15.0%]), and posterior to the IVC (2 [10.0%]) (Figure 1A). In 10 patients, tumors were adherent to adjacent major vessels: IVC (5 [50.0%]), renal vein (2 [20.0%]), splenic vein (2 [20.0%]), and superior mesenteric vein (1 [10.0%]) (Figure 1B). Among 5 patients with tumor adherence to the IVC, tumors were located along the posterior aspect of the IVC in 2 patients (40.5%) (patients 10 and 16). Patient 10 had a large tumor (9.5 cm), but this tumor was resected without difficulty (Figure 2). A concomitant left adrenalectomy was performed in patients 1 and 11 because of adhesion. All tumors were benign based on the final histologic examination, as follows: lymphangioma (7 [35.0%]), ganglioneuroma (3 [15.0%]), schwannoma (2 [10.0%]), paraganglioma (2 [10.0%]), Castleman disease (2 [10.0%]), cavernous hemangioma (1 [0.5%]), neurofibroma (1 [0.5%]), gastric duplication cyst (1 [0.5%]), and bronchogenic cyst (1 [0.5%]).
One procedure (5.3%) was converted to a laparotomy (patient 17) because of bleeding from veins draining into the adhered superior mesenteric vein. The median operative time was 117.5 minutes (range, 20-330 minutes) and median estimated blood loss was 50.0 mL (range, 5-500 mL). No patient needed a blood transfusion.
There was no perioperative mortality. Postoperative complications occurred in 2 patients (10.0%). Patient 5 had fluid collection at the surgical site (grade IIIa by the modified Clavien complication classification) and patient 20 had urinary retention (grade I). These complications were treated by percutaneous drainage and urinary catheterization, respectively, and had resolved at the time of discharge. The median length of postoperative hospital stay was 5 days (range, 2-11 days). After a mean follow-up of 18.0 months (range, 1-53 months), no patient showed evidence of recurrence.
When perioperative outcomes were compared for patients with large (≥5 cm) or small (<5 cm) tumors, those with large tumors required longer operation times and lost more blood, but there were no significant differences between the groups (Table 2). Postoperative complication rates and postoperative hospital stays were also not significantly different between patients with large or small tumors.
Patients with tumors adhering to major vessels (ie, IVC, renal vein, splenic vein, and superior mesenteric vein) required significantly longer operative times (P = .02), but lost no more blood and had similar lengths of hospital stays (Table 3).
In contrast to the benign tumors in the study population, malignant retroperitoneal tumors dominated (71.4%) in patients who underwent an open procedure (open group; Table 4). Patients in the open group had larger tumors, reported symptoms more frequently, required a longer operation, lost more blood, and spent more time in the hospital. One postoperative death occurred in the open group due to multiorgan failure in a patient who underwent pancreaticoduodenectomy due to a pleomorphic malignant fibrous histiocytoma.
Few reports exist on laparoscopic resection of nonadrenal retroperitoneal tumors, and the majority are case reports.5- 11 To our knowledge, the present study is the largest case series to show the feasibility and safety of the laparoscopic resection of nonadrenal retroperitoneal tumors. In the present study, all retroperitoneal tumors in various locations were safely approached by laparoscopy, even when a tumor was located along the posterior aspect of the IVC. Furthermore, the magnified view provided by laparoscopy enabled precise dissection of retroperitoneal tumors located in a deep, narrow space. All tumors but 1 were safely resected without injury to adjacent organs, with minimal intraoperative bleeding, and a low incidence of postoperative morbidity. In particular, large tumors (>5 cm) and tumors adjacent to major vessels were removed without significantly affecting perioperative outcomes.
Use of the laparoscopic approach to treat large tumors remains debatable8 and there is no established correlation between tumor size and the possibility of malignancy.17,22 Hence, no definitive guidelines have been issued regarding use of laparoscopy to remove benign tumors based on size. However, advances in radiologic techniques have made the differentiation of benign and malignant lesions more reliable.23,24 In the present study, all tumors were shown to be benign based on postoperative histopathologic evaluation. Thus, laparoscopic resection can be viewed as a first-line treatment option for tumors that are thought to be benign—even large retroperitoneal tumors. Some case reports have described the successful laparoscopic resection of large (>10 cm) retroperitoneal tumors.5,25 In the present study, a 9.5-cm retroperitoneal tumor that was adherent to the IVC was resected without complication. Furthermore, perioperative results did not differ between large and small tumors. However, patients with tumors larger than 10 cm were excluded for laparoscopic resection because large incisions would have been required to extract the specimens, thus reducing the benefits of minimally invasive operations. Moreover, if a tumor is large and heavy, laparoscopic manipulation is expected to be difficult.
Ten of our 20 patients had tumors adherent to neighboring major vessels. When a tumor adheres to important adjacent vessels, the risk of massive bleeding17 and injury to adjacent organs is increased. Therefore, meticulous dissection is necessary. In the present study, although the operative times were greater in the adhesion group, the presence of adhesions to an adjacent major vessel did not affect the clinical outcome. This suggests that laparoscopic resection of retroperitoneal tumors located near major vessels or vital structures is feasible and safe.
Although the disease entities differed between the 2 study groups, the clinical results were better in the laparoscopy group than in the open group. In particular, malignant tumors dominated in the open group and the invasion to adjacent organs and combined resection may have affected clinical outcomes unfavorably in this group. Although a number of successful trials on laparoscopic excision of malignant retroperitoneal tumors have been conducted,25,26 its use remains controversial. Usually, suspicious malignant lesions need wide surgical excision to ensure a safe surgical margin; hence, there are higher risks of injuring adjacent structures and of incomplete excision. Therefore, if a laparoscopically resected tumor is shown to be malignant on frozen section or postoperative histopathologic examination, open conversion or relaparotomy for wide excision should be considered. Still, there is a lack of long-term data on oncologic safety, such as survival and recurrence. If malignancy is suspected based on results of preoperative radiologic studies, an open operation may be preferred for oncologic safety. Thus, further evaluations are needed before the laparoscopic approach can be used routinely for malignant lesions.
The incidence of retroperitoneal tumors is too infrequent for most surgeons to gain sufficient experience in laparoscopic excision. For laparoscopic excision of a retroperitoneal tumor, techniques for approaching the retroperitoneal space, adequate mobilization of adjacent organs (eg, duodenum, spleen, and hepatic or splenic flexure of the colon) are necessary. Therefore, for an experienced surgeon who is adroit at laparoscopic adrenalectomy, distal pancreatectomy, splenectomy, or colectomy, laparoscopic resection of a retroperitoneal tumor can be performed easily.
This study demonstrates that laparoscopic resection of nonadrenal retroperitoneal tumors, even when tumors are large or adhere to adjacent vascular structures, is safe and feasible if there is no evidence of local invasion or malignancy on preoperative radiologic images.
Correspondence: Ho-Seong Han, MD, PhD, Department of Surgery, Seoul National University, Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Korea (email@example.com).
Accepted for Publication: November 30, 2009.
Author Contributions: Ho-Seong Han had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Ahn, Han, and Yoon. Acquisition of data: Ahn, Han, Yoon, Kim, Lee, Kang, and Cho. Analysis and interpretation of data: Ahn and Han. Drafting of the manuscript: Ahn, Yoon, Kim, Lee, Kang, and Cho. Critical revision of the manuscript for important intellectual content: Ahn and Han. Statistical analysis: Ahn. Obtained funding: Han. Administrative, technical, and material support: Ahn, Han, Yoon, Kim, Lee, Kang, and Cho. Study supervision: Han.
Financial Disclosure: None reported.
Funding/Support: This study was supported by grant 02-1004-005 from the Seoul National University Bundang Hospital Research Fund, Korea.